FREQOUT 4mhz

[Art]

I wouldn’t say “need”.
You’d get best results using any of the shrouded ones that will at least be loud at their resonant freq. That would be money better spent than on the transistor I think.
The pic could probably drive a small speaker through a series capacitor. I used a MAX232 as a buffer for a speaker, and small output transformer (MAX232 drives the audio positive and negative).

[Michael]

Not having any luck. I know the piezo is good -- I've tested it.

I'm probably missing something in set up or some register that needs to be modified?

I just put in --
PWM portc.4,50,6500

Piezo is 6500 hz. Hearing nothing.

PIC is 16C72, 8 bit antique.

[Michael]

Don't know if PWM is my only option. FREQOUT can't be used and SOUND is a sine wave right?

[Michael]

and that should be 127, not 50 for duty cycle -- typo

[Michael]

I think it may be this crap piezo I'm using --

https://www.ebay.com/itm/US-Stock-50...72.m2749.l2649

hard to work with. maybe someone can suggest an inexpensive one that they know works well. need low cost as this may be a product idea. 6500 hz is pretty high as well.

[richard]

Don't know if PWM is my only option. FREQOUT can't be used and SOUND is a sine wave right?

wrong
from manual

SOUND outputs TTL-level square waves. Thanks to the excellent I/O characteristics of the PIC MCU, a speaker can be driven through a capacitor. The value of the capacitor should be determined based on the frequencies of interest and the speaker load. Piezo speakers can be driven directly

I just put in --
PWM portc.4,127,6500

Piezo is 6500 hz. Hearing nothing.

pwm does not do what you have expected

@4mhz clock pwm output is 6500 cycles @200 hz


a 6500hz resonator can be driven at frequencies other than its resonant frequency

your chip has a pwm/ccp module , you could use HPWM

to get maximum noise you can drive the resonator bipolar mode between to output pins antiphased

I notice those resonators you linked have no connecter leads , how good is your soldering ?
they don't work if they have been cooked

[Michael]

Ok Richard thanks. I'll try SOUND and stick with it and yes, those transducers are something I've never dealt with -- they're a pain. Going to try something else.

[Michael]

Do you think these will work on a PIC output with the SOUND command at 2300 hz ? At least they're 5V.

https://www.ebay.com/itm/Gfortune-15...UAAOSwErFZ0-ze


Having problems getting piezo diaphragms and driver circuits to be very loud. barely hear them in fact. --Thank you

[mark_s]

Those are self resonating. They will buzz at 2300hz when 5 volts is applied. Look for "transducer".

Something like this
https://www.ebay.com/itm/AT-12-Piezo...gAAOSwZd1Vewuj